A light scattering instrument will be constructed which will be able, for the first time, to measure all of the information carried by light that has scattered from a solution of macromolecules. The instrument will be constructed according to principles established in a theoretical analysis which shows that there are as many as sixteen independent molecular parameters in a scattering experiment that (1) makes full use of polarization variables, (2) uses a scatter which is not small with respect to the wavelength of light, and (3) uses light that is resonant or nearly resonant with some of the subunits of the macromolecule. Of these sixteen parameters, at least five should be highly sensitive to the secondary and tertiary structure of the macromolecule. More specifically, they will be sensitive to changes in the relative positions of the resonating subunits of the polymer as it changes shape under varying conditions of temperature, pH, or ionic strength, or as it performs some metabolic task. The resonating subunits could be aromatic units occurring naturally in the polymer, or they could be small tags artificially attached. The use of dye tags resonant in the near ultraviolet should allow one to follow configurational changes in the tagged protein as it interacts with complex biological mixtures, provided only that the tag is resonant at longer wavelength than anything else in the mixture. This method is somewhat similar to fluorescence tagging, but is more subtle in that it works by optical interference from two or more tags on the same macromolecule, driven coherently by the incident light.